Brass instruments such as a trumpet and a horn are made of soft metal such as brass. For this reason, if the brass instrument is hit by something or is erroneously dropped, a dent is likely to occur on a circumferential surface of the brass instrument.
Conventionally, as a method for repairing a dent occurred in a metal bend part of a brass instrument or a woodwind instrument, there is a traditional method in which a dent ball and a steel ball are inserted into a dent in a tube, the dent ball is hit by the steel ball by swinging a tube main body, the dent ball is pushed into the dent, and the dent is pushed out to repair the dent. Such a repair method requires substantial time and cost, and also requires skillfulness. Further, for large musical instruments such as a tuba, there is a problem in that it is difficult to swing the tube main body.
As a repair device for solving such problems, Patent Literature 1 discloses, as shown in FIG. 4, a repair device for a brass instrument which is configured such that a steel ball 30 is reciprocated in a tube axis direction by a magnetic field generation device 31, and that a dent ball 32 is pushed into a dent 33 through this reciprocation movement. According to the repair device, it is possible to easily perform repair work without requiring a tube main body 34 to swing.
However, the method is the same as the conventional method in that it is necessary to perform repair work by sequentially exchanging the dent ball from the one having a small diameter to the one having a large diameter. For this reason, it is necessary to prepare a number of dent balls from a small dent ball having a small diameter to a dent ball having a large diameter, and for example, it is necessary to prepare about 80 kinds of dent balls having a different diameter for repairing a tube body having inner diameters of 8 to 30 mm. In addition, electrical equipment is essential. Further, the adjustment of the cycle time and the impact force of the steel ball 30 requires skillfulness.